U.S. patent application number 13/606291 was filed with the patent office on 2014-03-13 for coated article with low-e coating having absorbing layers for low film side reflectance and low visible transmission.
This patent application is currently assigned to Guardian Industries Corp.. The applicant listed for this patent is Anton Dietrich, Bernd DISTELDORF, Piotr Kokot, Adam Tokarz. Invention is credited to Anton Dietrich, Bernd DISTELDORF, Piotr Kokot, Adam Tokarz.
Application Number | 20140071524 13/606291 |
Document ID | / |
Family ID | 49162244 |
Filed Date | 2014-03-13 |
United States Patent
Application |
20140071524 |
Kind Code |
A1 |
DISTELDORF; Bernd ; et
al. |
March 13, 2014 |
COATED ARTICLE WITH LOW-E COATING HAVING ABSORBING LAYERS FOR LOW
FILM SIDE REFLECTANCE AND LOW VISIBLE TRANSMISSION
Abstract
Absorbing layers of a low-emissivity (low-E) coating are
designed to cause the coating to have a reduced film side
reflectance which is advantageous for aesthetic purposes. In
certain embodiments, the absorbing layers are metallic or
substantially metallic (e.g., NiCr or NiCrN.sub.x) and are
positioned in order to reduce or prevent oxidation of the absorbing
layers during optional heat treatment (e.g., thermal tempering,
heat bending, and/or heat strengthening). Coated articles according
to certain example embodiments of this invention may be used in the
context of insulating glass (IG) window units, other types of
windows, etc.
Inventors: |
DISTELDORF; Bernd;
(Mettlach, DE) ; Dietrich; Anton; (Fontnas,
CH) ; Kokot; Piotr; (Czestochowa, PL) ;
Tokarz; Adam; (Czestochowa, PL) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
DISTELDORF; Bernd
Dietrich; Anton
Kokot; Piotr
Tokarz; Adam |
Mettlach
Fontnas
Czestochowa
Czestochowa |
|
DE
CH
PL
PL |
|
|
Assignee: |
Guardian Industries Corp.
Auburn Hills
MI
|
Family ID: |
49162244 |
Appl. No.: |
13/606291 |
Filed: |
September 7, 2012 |
Current U.S.
Class: |
359/360 ;
359/359 |
Current CPC
Class: |
C03C 17/3435 20130101;
C03C 17/3626 20130101; C03C 17/3652 20130101; G02B 5/208 20130101;
C03C 17/366 20130101; C03C 17/3441 20130101; C03C 17/3644 20130101;
G02B 1/11 20130101; G02B 5/26 20130101; C03C 17/3681 20130101; C03C
17/3639 20130101; G02B 5/281 20130101; G02B 5/205 20130101 |
Class at
Publication: |
359/360 ;
359/359 |
International
Class: |
G02B 5/26 20060101
G02B005/26 |
Claims
1. A coated article including a coating supported by a glass
substrate, the coating comprising: first and second infrared (IR)
reflecting layers comprising silver, wherein said IR reflecting
layers are spaced apart from one another, and wherein the first IR
reflecting layer is located closer to the glass substrate than is
the second IR reflecting layer; a first substantially metallic or
metallic absorption layer comprising Ni and/or Cr located such that
the first absorption layer is located between the first and second
IR reflecting layers, wherein the first absorption layer is
sandwiched between and contacting first and second dielectric
layers comprising silicon nitride; and a second substantially
metallic or metallic absorption layer comprising Ni and/or Cr
located such that both the first and second IR reflecting layers
are located between the glass substrate and the second absorption
layer, wherein the second absorption layer is located between and
contacting the second IR reflecting layer and a third dielectric
layer comprising silicon nitride.
2. The coated article of claim 1, wherein said first and second
absorption layers each comprise NiCr.
3. The coated article of claim 1, wherein said first and second
absorption layers each comprise NiCrN.sub.x.
4. The coated article of claim 1, wherein said first and second
absorption layers each comprise from 1-15% nitrogen (atomic %).
5. The coated article of claim 1, wherein said first and second IR
reflecting layers are spaced apart by at least, moving away from
the glass substrate: a layer comprising tin oxide, said first layer
comprising silicon nitride, said first absorption layer, said
second dielectric layer comprising silicon nitride, another layer
comprising tin oxide, and a layer comprising zinc oxide.
6. The coated article of claim 1, wherein no metallic or
substantially metallic absorption layer is located between the
first IR reflecting layer and the glass substrate.
7. The coated article of claim 1, wherein only two IR reflecting
layers comprising silver are contained in the coating.
8. The coated article of claim 1, wherein the first absorption
layer is from about 35-75 angstroms (.ANG.) thick.
9. The coated article of claim 1, wherein the second absorption
layer is from about 23-48 angstroms (.ANG.) thick.
10. The coated article of claim 1, wherein the first absorption
layer is substantially thicker than the second absorption
layer.
11. The coated article of claim 1, wherein said coated article has
a visible transmission of from about 20-43%, measured
monolithically.
12. The coated article of claim 1, wherein said coated article has
a visible transmission of from about 24-36%, measured
monolithically.
13. The coated article of claim 1, wherein the coated article is
thermally tempered.
14. The coated article of claim 1, wherein the coated article is
not heat treated.
15. The coated article of claim 1, wherein the coating contains no
more than two metallic or substantially metallic absorption layers
consisting essentially of NiCr or NiCrN.sub.x.
16. The coated article of claim 1, wherein the third layer
comprising silicon nitride is an uppermost layer of the
coating.
17. The coated article of claim 1, wherein said first IR reflecting
layer and said first absorption layer are spaced apart by at least,
moving away from the glass substrate: a layer comprising an oxide
of NiCr, a layer comprising tin oxide, and the first layer
comprising silicon nitride.
18. The coated article of claim 1, wherein the coated article has a
visible film side reflectance (RfY), measured monolithically, of
less than or equal to 26%.
19. The coated article of claim 1, wherein the coated article has a
visible film side reflectance (RfY), measured monolithically, of
less than or equal to 24%.
20. The coated article of claim 1, wherein a substantially oxided
layer comprising an oxide of NiCr is located over and directly
contacting the first IR reflecting layer.
21. The coated article of claim 1, wherein a metallic or
substantially metallic layer comprising NiCr and/or NiCrN.sub.x is
located over and directly contacting the first IR reflecting
layer.
22. A coated article including a coating supported by a glass
substrate, the coating comprising: first and second infrared (IR)
reflecting layers, wherein said IR reflecting layers are spaced
apart from one another, and wherein the first IR reflecting layer
is located closer to the glass substrate than is the second IR
reflecting layer; a first substantially metallic or metallic
absorption layer located such that the first absorption layer is
located between the first and second IR reflecting layers, wherein
the first absorption layer is sandwiched between and contacting
first and second dielectric layers comprising silicon nitride; and
a second substantially metallic or metallic absorption layer
located such that both the first and second IR reflecting layers
are located between the glass substrate and the second absorption
layer, wherein the second absorption layer is located between and
contacting the second IR reflecting layer and a third dielectric
layer comprising silicon nitride.
Description
[0001] This invention relates to a coated article including a
low-emissivity (low-E) coating. In certain example embodiments,
absorbing layers of the low-E coating are positioned/designed to
cause the coating to have both (i) a low visible transmission
(e.g., no greater than 45%, more preferably no greater than 40%,
and most preferably no greater than 35%), and (ii) a reduced
visible film side reflectance. An upper absorbing layer may be
provided in an upper stack and another absorbing layer may be
provided in a middle stack of the low-E coating. In certain example
embodiments, the absorbing layers are metallic or substantially
metallic. The absorbing layer in the middle stack may be provided
between first and second nitride layers (e.g., silicon nitride
based layers), whereas the absorbing layer in the upper stack may
be provided between a nitride layer and a metallic or substantially
metallic infrared (IR) reflecting layer, in order to reduce or
prevent oxidation of the absorbing layers during optional heat
treatment (e.g., thermal tempering, heat bending, and/or heat
strengthening) and/or manufacturing thereby permitting predictable
coloration and optical characteristics to be achieved. Coated
articles according to certain example embodiments of this invention
may be used in the context of insulating glass (IG) window units,
vehicle windows, other types of windows, or in any other suitable
application.
BACKGROUND OF THE INVENTION
[0002] Coated articles are known in the art for use in window
applications such as insulating glass (IG) window units, vehicle
windows, and/or the like. It is known that in certain instances, it
is desirable to heat treat (e.g., thermally temper, heat bend
and/or heat strengthen) such coated articles for purposes of
tempering, bending, or the like in certain example instances. Heat
treatment of coated articles typically requires use of
temperature(s) of at least 580 degrees C., more preferably of at
least about 600 degrees C. and still more preferably of at least
620 degrees C. Such high temperatures (e.g., for 5-10 minutes or
more) often cause coatings to break down and/or deteriorate or
change in an unpredictable manner. Thus, it is desirable for
coatings to be able to withstand such heat treatments (e.g.,
thermal tempering), if desired, in a predictable manner that does
not significantly damage the coating.
[0003] In certain situations, designers of coated articles strive
for a combination of desirable visible transmission, desirable
color, low emissivity (or emittance), and low sheet resistance
(R.sub.S). Low-emissivity (low-E) and low sheet resistance
characteristics permit such coated articles to block significant
amounts of IR radiation so as to reduce for example undesirable
heating of vehicle or building interiors. Often, more IR radiation
being blocked (including reflected) is accompanied by less visible
transmission.
[0004] U.S. Pat. No. 7,597,965 discloses a low-E coating with an
NiCr absorber layer in the lower dielectric stack. However, the
example coating in the '965 patent is designed for a high visible
transmission, and indeed has a visible transmission (T.sub.vis or
TY) of 59%. Lower visible transmissions are often desirable. For
example, it is often desirable for aesthetic and/or optical
purposes to provide coated articles (including low-E coatings)
having visible transmissions of no greater than 45%, more
preferably no greater than 40%, and sometimes no greater than about
35%. However, when visible transmission of a coated article is
reduced via a low-E coating design, the film side reflectance of
the coating typically increases.
[0005] U.S. Pat. No. 7,648,769 discloses a low-E coating with an
NiCr absorber layer provided in the middle dielectric stack, but
not in the upper and lower dielectric stacks of the coating (e.g.,
see FIG. 1 of the '769 patent). Example 1 in the '769 patent
realizes, measured monolithically, a visible transmission of 54.5%
and a film side reflectance of 19.5%, and when measured in an
insulating glass (IG) window unit the values change to a visible
transmission of 50% and a film side reflectance of 23%. Example 2
in the '769 patent has a higher visible transmission and realizes,
measured monolithically, a visible transmission of 67.5% and a film
side reflectance of 11.5%, and when measured in an insulating glass
(IG) window unit the values change to a visible transmission of 62%
and a film side reflectance of 17%. The examples in the '769 patent
teach that when visible transmission goes down, film side
reflectance goes up.
[0006] It will also be explained herein, in the detailed
description section, that providing a given absorber layer only in
the middle dielectric stack of a low-E coating having a visible
transmission of about 40% results in an undesirably high visible
film side reflectance (RfY) of over 30% (measured
monolithically).
[0007] Thus, it will be appreciated that it has been difficult to
achieve coated articles, including low-E coatings, having a
combination of both (i) desirably low visible transmission, and
(ii) low film side reflectance. It will be apparent to those
skilled in the art that there exists a need in the art for a coated
article having low emissivity (or low sheet resistance) and a
combination of both low visible transmission (e.g., no greater than
45%, more preferably no greater than about 40%, and most preferably
no greater than about 35%) and low film side reflectance.
BRIEF SUMMARY OF EXAMPLE EMBODIMENTS OF THE INVENTION
[0008] A coated article includes a low-E coating. In certain
example embodiments, absorbing layers in the low-E coating are
positioned/designed to cause the low-E coating to have both (i) a
low visible transmission (e.g., no greater than 45%, more
preferably no greater than 40%, and most preferably no greater than
35%), and (ii) low visible film side reflectance which is
advantageous for aesthetic purposes. An absorbing layer is be
provided in an upper stack of the low-E coating and another
absorbing layer is provided in a middle stack of the low-E coating,
and in certain double-silver embodiments no similar absorbing layer
is provided in the lower stack of the low-E coating. The absorbing
layers are metallic or substantially metallic (e.g., NiCr or
NiCrN.sub.x). In certain example embodiments the absorbing layer in
the middle stack is provided between first and second nitride
layers (e.g., silicon nitride based layers), and the absorbing
layer in the upper stack is provided between a nitride layer and a
metallic or substantially metallic infrared (IR) reflecting layer,
in order to reduce or prevent oxidation of the absorbing layers
during optional heat treatment (e.g., thermal tempering, heat
bending, and/or heat strengthening) and/or manufacturing thereby
permitting predictable coloration and optical characteristics to be
achieved. It has been found that the use of such absorbing layers
in the top and middle portions of the coating surprisingly and
unexpectedly allows for a combination of low visible transmission
and low film side reflectance to be simultaneously realized. Coated
articles according to certain example embodiments of this invention
may be used in the context of IG window units, vehicle windows,
other types of windows, or in any other suitable application.
[0009] In certain example embodiments of this invention, there is
provided a coated article including a coating supported by a glass
substrate, the coating comprising: first and second infrared (IR)
reflecting layers (e.g., of or including silver), wherein said IR
reflecting layers are spaced apart from one another, and wherein
the first IR reflecting layer is located closer to the glass
substrate than is the second IR reflecting layer; a first
substantially metallic or metallic absorption layer (e.g., of or
including NiCr and/or NiCrN.sub.x) located such that the first
absorption layer is located between the first and second IR
reflecting layers, wherein the first absorption layer is sandwiched
between and contacting first and second dielectric layers
comprising silicon nitride; and a second substantially metallic or
metallic absorption layer (e.g., of or including NiCr and/or
NiCrN.sub.x) located such that both the first and second IR
reflecting layers are located between the glass substrate and the
second absorption layer, wherein the second absorption layer is
located between and contacting the second IR reflecting layer and a
third dielectric layer comprising silicon nitride.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] FIG. 1 is a cross sectional view of a coated article
according to an example embodiment of this invention.
[0011] FIG. 2 is a cross sectional view showing the coated article
of FIG. 1 provided in an IG window unit according to an example
embodiment of this invention.
DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION
[0012] Coated articles herein may be used in applications such as
IG window units, vehicle windows, monolithic architectural windows,
residential windows, and/or any other suitable application that
includes single or multiple glass substrates.
[0013] In certain example embodiments of this invention, the
coating includes a double-silver stack (as shown in FIG. 1),
although this invention is not so limited in all instances.
[0014] For example, in certain example embodiments of this
invention, heat treated or non-heat-treated coated articles having
multiple IR reflecting layers (e.g., two spaced apart silver based
layers) are capable of realizing a sheet resistance (R.sub.S) of
less than or equal to 3.0 (more preferably less than or equal to
2.5, even more preferably less than or equal to 2.1, and most
preferably less than or equal to 2.0). The terms "heat treatment"
and "heat treating" as used herein mean heating the article to a
temperature sufficient to achieve thermal tempering, heat bending,
and/or heat strengthening of the glass inclusive article. This
definition includes, for example, heating a coated article in an
oven or furnace at a temperature of least about 580 degrees C.,
more preferably at least about 600 degrees C., for a sufficient
period to allow tempering, bending, and/or heat strengthening. In
certain instances, the HT may be for at least about 4 or 5 minutes.
The coated article may or may not be heat treated in different
embodiments of this invention.
[0015] FIG. 1 is a side cross sectional view of a coated article
according to an example non-limiting embodiment of this invention.
The coated article includes substrate 1 (e.g., clear, green,
bronze, or blue-green glass substrate from about 1.0 to 10.0 mm
thick, more preferably from about 1.0 mm to 3.5 mm thick), and
low-E coating (or layer system) 30 provided on the substrate 1
either directly or indirectly. The coating (or layer system) 30
includes, for example: bottom dielectric silicon nitride layer 3
which may be Si.sub.3N.sub.4, of the Si-rich type for haze
reduction, or of any other suitable stoichiometry silicon nitride
in different embodiments of this invention, first lower contact
layer 7 (which contacts bottom IR reflecting layer 9), first
conductive and preferably metallic or substantially metallic
infrared (IR) reflecting layer 9, first upper contact layer 11
(which contacts layer 9), dielectric layer 13, dielectric silicon
nitride based and/or inclusive layer 14, metallic or substantially
metallic absorbing layer 4 (e.g., of or including NiCr,
NiCrN.sub.x, or the like), additional dielectric silicon nitride
layer 14' which may be Si.sub.3N.sub.4, of the Si-rich type for
haze reduction, or of any other suitable stoichiometry silicon
nitride, tin oxide inclusive based and/or inclusive interlayer 15,
second lower contact layer 17 (which contacts IR reflecting layer
19), second conductive and preferably metallic or substantially
metallic IR reflecting layer 19, metallic or substantially metallic
absorbing layer 25 (e.g., of or including NiCr, NiCrN.sub.x, or the
like) which is located over and contacting the upper IR reflecting
layer 19, and overcoat dielectric silicon nitride layer 26 which
may be Si.sub.3N.sub.4, of the Si-rich type for haze reduction, or
of any other suitable stoichiometry silicon nitride. The "contact"
layers 7, 11, and 17 each contact at least one IR reflecting layer
(e.g., layer based on Ag). The aforesaid sputter-deposited layers
3-26 make up low-E, (i.e., low emissivity) coating 30 that is
provided on glass or plastic substrate 1.
[0016] In monolithic instances, the coated article includes only
one glass substrate 1 as illustrated in FIG. 1. However, monolithic
coated articles herein may be used in devices such as laminated
vehicle windshields, IG window units, and the like. As for IG
window units, an IG window unit may include two spaced apart glass
substrates. An example IG window unit is illustrated and described,
for example, in U.S. Patent Document No. 2004/0005467, the
disclosure of which is hereby incorporated herein by reference.
FIG. 2 shows an example IG window unit including the coated glass
substrate shown in FIG. 1 coupled to another glass substrate 2 via
spacer(s), sealant(s) 40 or the like, with a gap 50 being defined
therebetween. This gap 50 between the substrates in IG unit
embodiments may in certain instances be filled with a gas such as
argon (Ar) (in addition to including air). An example IG unit may
comprise a pair of spaced apart clear glass substrates each about
3-6 mm thick, one of which is coated with a coating 30 herein in
certain example instances, where the gap 50 between the substrates
may be from about 5 to 30 mm, more preferably from about 10 to 20
mm, and most preferably about 16 mm. In certain example instances,
the coating 30 may be provided on the interior surface of either
substrate facing the gap (the coating is shown on the interior
major surface of substrate 1 in FIG. 2 facing the gap 50, but
instead could be on the interior major surface of substrate 2
facing the gap 50). Either substrate 1 or substrate 2 may be the
outermost substrate of the IG window unit at the building exterior
(e.g., in FIG. 2 the substrate 1 is the substrate closest to the
building exterior).
[0017] Absorption layer 4 is, in certain example embodiments of
this invention, located between and contacting nitride based
dielectric layers 14 and 14'. In certain example embodiments, each
of layers 14 and 14' surrounding the absorption layer 4 is a
nitride layer and is substantially or entirely non-oxidized.
Absorption layer 25 is, in certain example embodiments of this
invention, located between and contacting the metallic or
substantially metallic IR reflecting layer 19 and nitride based
dielectric layer 26. In certain example embodiments, each of layers
19 and 26 surrounding the absorption layer 25 is substantially or
entirely non-oxidized. Optionally, the outermost portion of layer
26 may be oxided if it is the outermost layer of the coating 30 and
exposed to atmosphere. The use of nitride layers 14, 14' and 26,
and metallic or substantially metallic layer 19, around the
absorber layers 4 and 25 is advantageous in that it helps prevent
(or reduce the likelihood of) the absorption layers 4, 25 from
being oxidized during heat treatment, thereby better allowing the
absorption layers 4, 25 to perform an intended function, in
particular absorbing at least some amount (e.g., at least 5%, more
preferably at least 10%) of visible light. It will be appreciated
that if a layer becomes too oxidized during heat treatment or the
like, it no longer can function as an adequate absorption
layer.
[0018] In certain example embodiments of this invention, absorption
layers 4 and 25 may be of or include NiCr (any suitable ratio or
Ni:Cr), and may or may not be nitrided (NiCrN.sub.x). Absorption
layers 4 and 25 are located between and contacting substantially
non-oxided layers as shown in FIG. 1. In certain example
embodiments, each of the nitride based layers 14, 14', 26
surrounding the absorption layers 4, 25 is a nitride layer and is
substantially or entirely non-oxidized, and IR reflecting layer 19
is also substantially or entirely non-oxidized. In certain example
embodiments, absorption layers 4, 25 may comprise from 0-10%
oxygen, more preferably from 0-5% oxygen, and most preferably from
0-2% oxygen (atomic %). In certain example embodiments, one or both
absorption layers 4, 25 comprise from 0-20% nitrogen, more
preferably from 1-15% nitrogen, and most preferably from about
1-12% nitrogen (atomic %). While NiCr is a preferred material for
the absorption layers 4 and 25, it is possible that other materials
may instead be used. For example, in certain other heat treatable
example embodiments of this invention, the absorption layers 4
and/or 25 may be of or include Ni, Cr, NiCrN.sub.x, CrN, ZrN, or
TiN. In non-heat treatable embodiments, any of the aforesaid
materials may be used for the absorption/absorbing layers 4 and/or
25, as well as other materials such as Ti, Zr, NiOx or the
like.
[0019] The absorbing layers 4 and 25 of the low-E coating 30 are de
signed to cause the coating 30 to have a lower visible
transmission, desirable coloration, and low film side reflectance.
In certain example embodiments, the metallic or substantially
metallic absorbing layer (e.g., NiCr or NiCrN.sub.x) 4 may be from
about 20-120 angstroms (.ANG.) thick, more preferably from about
35-75 angstroms (.ANG.) thick, and most preferably from about 50-70
angstroms (.ANG.) thick. In certain example embodiments, the upper
metallic or substantially metallic absorbing layer (e.g., NiCr or
NiCrN.sub.x) 25 may be from about 15-70 angstroms (.ANG.) thick,
more preferably from about 23-48 angstroms (.ANG.) thick, and most
preferably from about 27-43 angstroms (.ANG.) thick. In certain
example embodiments, the upper absorbing layer 25 may be thinner
than the lower absorbing layer 4. For example, in certain example
embodiments, the upper absorbing layer 25 may be at least 10
angstroms (.ANG.) thinner (more preferably at least 20 angstroms
thinner) than the lower absorbing layer 4, in order to provide for
desirable optical characteristics of the coated article. It has
been found that a combination of low visible transmission, reduced
visible film side reflectance, and desirable optical
characteristics can be achieved by having absorber layers both in
the middle dielectric portion of the stack (see absorber layer 4)
and by providing another absorber layer 25 in the upper portion of
the stack above the top IR reflecting layer 19, as it has been
found that moving significant absorption to the top of the stack
via layer 25 results in reduced film side reflectance compared to
providing absorber layer only between the IR reflecting layers,
while still allowing for desirable optical characteristics such as
color at angle, etc. via absorption layer 4 in the middle portion
of the stack.
[0020] Thus, an absorbing layer 25 is provided in the upper stack
(above the upper Ag based IR reflecting layer 19), and a second
absorbing layer 4 is provided in the middle portion of the stack
(between the IR reflecting layers 9, 19). Preferably, in certain
double-silver embodiments (i.e., where the low-E coating has two
Ag-based IR reflecting layers), no similar absorbing layer is
provided below the lower IR reflecting layer 9. In other words,
while absorber layers 4 and 25 are provided in middle and upper
portions of the coating, there is no similar absorber layer between
nitrides provided below the bottom IR reflecting layer 9.
[0021] Dielectric layers 3, 14, 14' and 26 may be of or include
silicon nitride in certain embodiments of this invention. Silicon
nitride layers 3, 14, 14' and 26 may, among other things, improve
heat-treatability of the coated articles and protect the absorbing
layers during optional HT, e.g., such as thermal tempering or the
like. One or more of the silicon nitride of layers 3, 14, 14' and
26 may be of the stoichiometric type (i.e., Si.sub.3N.sub.4), or
alternatively of the Si-rich type of silicon nitride in different
embodiments of this invention. The presence of free Si in a Si-rich
silicon nitride inclusive layer 3 may allow certain atoms such as
sodium (Na) which migrate outwardly from the glass 1 during HT to
be more efficiently stopped by the Si-rich silicon nitride
inclusive layer(s) before they can reach the silver 9 and damage
the same. It is believed that the Si-rich Si.sub.xN.sub.y can
reduce the amount of damage done to the silver layer(s) during HT
in certain example embodiments of this invention thereby allowing
sheet resistance (R.sub.S) to decrease or remain about the same in
a satisfactory manner. Moreover, it is believed that the Si-rich
Si.sub.xN.sub.y can reduce the amount of damage (e.g., oxidation)
done to absorbing layer 4 (and/or 25) during HT in certain example
optional embodiments of this invention. In certain example
embodiments, when Si-rich silicon nitride is used, the Si-rich
silicon nitride layer as deposited may be characterized by
Si.sub.xN.sub.y layer(s), where x/y may be from 0.76 to 1.5, more
preferably from 0.8 to 1.4, still more preferably from 0.82 to 1.2.
Moreover, in certain example embodiments, before and/or after HT
the Si-rich Si.sub.xN.sub.y layer(s) may have an index of
refraction "n" of at least 2.05, more preferably of at least 2.07,
and sometimes at least 2.10 (e.g., 632 nm) (note: stoichiometric
Si.sub.3N.sub.4 which may also be used has an index "n" of
2.02-2.04). It is noted that n and k tend to drop due to heat
treatment. Any and/or all of the silicon nitride layers discussed
herein may be doped with other materials such as stainless steel or
aluminum in certain example embodiments of this invention. For
example, any and/or all silicon nitride layers discussed herein may
optionally include from about 0-15% aluminum, more preferably from
about 1 to 10% aluminum, in certain example embodiments of this
invention. The silicon nitride may be deposited by sputtering a
target of Si or SiAl, in an atmosphere having argon and nitrogen
gas, in certain embodiments of this invention. Small amounts of
oxygen may also be provided in certain instances in the silicon
nitride layers.
[0022] Infrared (IR) reflecting layers 9 and 19 are preferably
substantially or entirely metallic and/or conductive, and may
comprise or consist essentially of silver (Ag), gold, or any other
suitable IR reflecting material. IR reflecting layers 9 and 19 help
allow the coating to have low-E and/or good solar control
characteristics. The IR reflecting layers may, however, be slightly
oxidized in certain embodiments of this invention.
[0023] Contact layer 11 may be of or include nickel (Ni) oxide,
chromium/chrome (Cr) oxide, NiCr, or a nickel alloy oxide such as
nickel chrome oxide (NiCrO.sub.x), or other suitable material(s),
in certain example embodiments of this invention. The use of for
example, NiCrO.sub.x in layer 11 allows durability to be improved.
The NiCrO.sub.x of layer 11 may be fully oxidized in certain
embodiments of this invention (i.e., fully stoichiometric), or
alternatively may only be partially oxidized. In certain instances,
the NiCrO.sub.x layer 11 may be at least about 50% oxidized.
Contact layer 11 (e.g., of or including an oxide of Ni and/or Cr)
may or may not be oxidation graded in different embodiments of this
invention. Oxidation grading means that the degree of oxidation in
the layer changes throughout the thickness of the layer so that for
example a contact layer may be graded so as to be less oxidized at
the contact interface with the immediately adjacent IR reflecting
layer 9 than at a portion of the contact layer(s) further or
more/most distant from the immediately adjacent IR reflecting
layer. Descriptions of various types of oxidation graded contact
layers are set forth in U.S. Pat. No. 6,576,349, the disclosure of
which is hereby incorporated herein by reference. Contact layer 11
(e.g., of or including an oxide of Ni and/or Cr) may or may not be
continuous in different embodiments of this invention across the
entire IR reflecting layer 9. In certain alternative example
embodiments of this invention, layer 11 may instead be made as a
metallic or substantially metallic absorption layer (e.g., NiCr or
NiCrN.sub.x) like layer 25.
[0024] Dielectric layers 13 and 15 may be of or include tin oxide
in certain example embodiments of this invention. However, as with
other layers herein, other materials may be used in different
instances. Interlayer 15 of or including tin oxide is provided
under IR reflecting layer 19 so as to be located between silicon
nitride layer 14' and zinc oxide layer 17. The use of such a tin
oxide inclusive interlayer 15 results in numerous improvements
compared to a situation where the layer is not provided. For
example, it has been found that the use of such a tin oxide
inclusive interlayer 15 results in a coated article which is
capable of realizing: (a) less visible transmission shift due to
heat treatment, (b) higher visible transmission following heat
treatment; (c) less shifting of certain color value(s) due to heat
treatment, (d) substantially neutral coloration following heat
treatment; (e) more stable, or even decreasing, sheet resistance
due to heat treatment, (f) lower sheet resistance and thus lower
emissivity following heat treatment, (g) improved haze
characteristics following heat treatment, and/or (h) improved
mechanical durability such as scratch resistance before and/or
after heat treatment. Thus, in certain example embodiments of this
invention, coated articles may be taken to higher temperatures
during heat treatment and/or for longer times without suffering
undesirable significant transmission drops and/or increases in
sheet resistance. In certain alternative embodiments, it is
possible to dope the tin oxide of layer 15 with other materials
such as Al, Zn or the like. Alternatively, other metal oxide(s) may
be used for layer 15 in certain instances.
[0025] Lower contact layers 7 and/or 17 in certain embodiments of
this invention are of or include zinc oxide (e.g., ZnO). The zinc
oxide of layers 7 and 17 may contain other materials as well such
as Al (e.g., to form ZnAlO.sub.x). For example, in certain example
embodiments of this invention, one or more of zinc oxide layers 7,
17 may be doped with from about 1 to 10% Al, more preferably from
about 1 to 5% Al, and most preferably about 1 to 4% Al.
[0026] Other layer(s) below or above the illustrated coating may
also be provided. Thus, while the layer system or coating is on or
"supported by" substrate 1 (directly or indirectly), other layer(s)
may be provided therebetween. Thus, for example, the coating of
FIG. 1 may be considered "on" and "supported by" the substrate 1
even if other layer(s) are provided between layer 3 and substrate
1. Moreover, certain layers of the illustrated coating may be
removed in certain embodiments, while others may be added between
the various layers or the various layer(s) may be split with other
layer(s) added between the split sections in other embodiments of
this invention without departing from the overall spirit of certain
embodiments of this invention.
[0027] While various thicknesses and materials may be used in
layers in different embodiments of this invention, example
thicknesses and materials for the respective layers on the glass
substrate 1 in the FIG. 1 embodiment are as follows, from the glass
substrate outwardly (note that the NiCr layers may or may not be
partially nitrided):
TABLE-US-00001 Example Materials/Thicknesses; FIG. 1 Embodiment
Layer Glass Preferred More Example (1-10 mm thick) Range (.ANG.)
Preferred (.ANG.) (.ANG.) Si.sub.xN.sub.y (layer 3) 40-750 .ANG.
250-600 .ANG. 419 .ANG. ZnO.sub.x (layer 7) 10-300 .ANG. 60-150
.ANG. 80 .ANG. Ag (layer 9) 50-200 .ANG. 80-130 .ANG. 119 .ANG.
NiCrO.sub.x (layer 11) 10-100 .ANG. 12-40 .ANG. 25 .ANG. SnO.sub.2
(layer 13) 0-1,000 .ANG. 200-700 .ANG. 545 .ANG. Si.sub.xN.sub.y
(layer 14) 50-450 .ANG. 80-200 .ANG. 120 .ANG. NiCr (layer 4) 35-75
.ANG. 50-70 .ANG. 62 .ANG. Si.sub.xN.sub.y (layer 14') 40-450 .ANG.
70-300 .ANG. 151 .ANG. SnO.sub.2 (layer 15) 30-250 .ANG. 50-200
.ANG. 80 .ANG. ZnO.sub.x (layer 17) 10-300 .ANG. 40-130 .ANG. 80
.ANG. Ag (layer 19) 50-200 .ANG. 70-180 .ANG. 153 .ANG. NiCr (layer
25) 23-48 .ANG. 27-43 .ANG. 35 .ANG. Si.sub.xN.sub.y (layer 26)
40-500 .ANG. 70-400 .ANG. 317 .ANG.
[0028] It can be seen that the bottom absorber layer 4 is thicker
than the upper absorber layer 25. For example, in certain
embodiments the bottom absorber layer 4 is at least 10 .ANG.
thicker than the upper absorber layer 25, more preferably at least
20 .ANG. thicker, and even more preferably at least 25 .ANG.
thicker. Also, it can be seen that for absorber layer 4, the bottom
silicon nitride layer 14 is thinner than the top silicon nitride
layer 14'. For example, surrounding absorber layer 4, in certain
embodiments the bottom silicon nitride layer 14 is at least 10
.ANG. thinner than the top silicon nitride layer 14', more
preferably at least about 20 .ANG. or 25 .ANG. thinner.
[0029] In certain example embodiments of this invention, coated
articles herein may have the following optical and solar
characteristics set forth in Table 2 when measured monolithically.
The sheet resistances (R.sub.S) herein take into account all IR
reflecting layers (e.g., silver layers 9, 19).
TABLE-US-00002 Optical/Solar Characteristics (Monolithic; pre-HT)
Characteristic General More Preferred Most Preferred R.sub.s
(ohms/sq.): <=3.5 <=2.5 <=2.2 E.sub.n: <=0.07 <=0.04
<=0.03 T.sub.vis (Ill, C 2.degree.): 20-45% 20-43% 24-36%
R.sub.fY (Ill. C, 2 deg.): <=29% <=26% <=24% R.sub.gY
(Ill. C, 2 deg.): <=25% <=22% <=18%
[0030] In certain example embodiments, coated articles herein may
have the following characteristics, measured monolithically for
example, after heat treatment (HT):
TABLE-US-00003 Optical/Solar Characteristics (Monolithic; post-HT)
Characteristic General More Preferred Most Preferred R.sub.s
(ohms/sq.): <=3.0 <=2.1 <=1.9 E.sub.n: <=0.07 <=0.04
<=0.03 T.sub.vis (Ill. C 2.degree.): 20-45% 20-43% 24-36%
R.sub.fY (Ill. C, 2 deg.): <=29% <=26% <=24% R.sub.gY
(Ill. C, 2 deg.): <=25% <=22% <=18%
[0031] Moreover, in certain example laminated embodiments of this
invention, coated articles herein which have been optionally heat
treated to an extent sufficient for tempering, and which have been
coupled to another glass substrate to form an IG unit, may have the
following IG unit optical/solar characteristics in a structure as
shown in FIG. 2 (e.g., where the two glass sheets are 4 mm thick
and 6 mm thick respectively of clear glass with a 16 mm gap
therebetween filled with 90/10 argon/air). It can be seen that the
film side reflection increases when placed in an IG window
unit.
TABLE-US-00004 Example Optical Features (IG Unit pre or post-HT)
Characteristic General More Preferred T.sub.vis (or TY)(Ill. C
2.degree.): 18-45% 20-33% a*.sub.t (Ill. C 2.degree.): -9 to +1.0
-7 to 0.0 b*.sub.t (Ill. C 2.degree.): -10 to +10 -5 to +5 R.sub.fY
(Ill. C, 2 deg.): <=31% <=28% a*.sub.f (Ill. C, 2.degree.):
-6 to +8 -4 to +4 b*.sub.f (Ill. C, 2.degree.): -6 to +12 -2 to +9
R.sub.gY (Ill. C, 2 deg.): 10-30% 15-25% a*.sub.g (Ill. C,
2.degree.): -7 to +4 -5 to +1 b*.sub.g (Ill. C, 2.degree.): -16 to
+5 -14 to 0
[0032] The following examples are provided for purposes of example
only, and are not intended to be limiting unless specifically
claimed.
EXAMPLES
[0033] The following Example 1 was made via sputtering on 6 mm
thick clear glass substrate so as to have approximately the layer
stack set forth below. Example 1 is according to example
embodiments of this invention as shown in FIG. 1, whereas the
Comparative Example (CE) below has an NiCr absorbing layer only in
the middle of the stack and is provided for purposes of comparison.
Example 1 had approximately the following layer stack, where the
thicknesses are in units of angstroms (.ANG.), and the NiCr
absorbing layers 4 and 25 were slightly nitrided.
Example 1
TABLE-US-00005 [0034] Layer Glass (6 mm thick) Thickness (.ANG.)
Si.sub.xN.sub.y (layer 3) 419 .ANG. ZnO.sub.x (layer 7) 80 .ANG. Ag
(layer 9) 119 .ANG. NiCrO.sub.x (layer 11) 25 .ANG. SnO.sub.2
(layer 13) 545 .ANG. Si.sub.xN.sub.y (layer 14) 120 .ANG. NiCr
(layer 4) 62 .ANG. Si.sub.xN.sub.y (layer 14') 151 .ANG. SnO.sub.2
(layer 15) 80 .ANG. ZnO.sub.x (layer 17) 80 .ANG. Ag (layer 19) 153
.ANG. NiCr (layer 25) 35 .ANG. Si.sub.3N.sub.4 (layer 26) 317
.ANG.
[0035] The Comparative Example (CE) had a NiCr absorbing layer
similar to those in Example 1, but in the CE the sole absorbing
layer was located only in the middle stack between the silver
layers. The CE had the following layer stack from the glass
outwardly.
TABLE-US-00006 COMPARATIVE EXAMPLE Layer Glass (6 mm thick)
Thickness (.ANG.) Si.sub.xN.sub.y 257 .ANG. ZnO.sub.x 100 .ANG. Ag
77 .ANG. NiCrO.sub.x 25 .ANG. SnO.sub.2 530 .ANG. Si.sub.xN.sub.y
120 .ANG. NiCr 134 .ANG. Si.sub.xN.sub.y 151 .ANG. SnO.sub.2 80
.ANG. ZnO.sub.x 80 .ANG. Ag 197 .ANG. NiCrO.sub.x 25 .ANG.
SnO.sub.2 142 .ANG. Si.sub.xN.sub.y 210 .ANG.
[0036] Set forth below are the optical characteristics of Example 1
compared to those of the Comparative Example (CE), measured
monolithically post-HT.
TABLE-US-00007 COMPARISON BETWEEN EXAMPLE 1 AND COMPARATIVE EXAMPLE
Characteristic Ex. 1 Comparative Example T.sub.vis (or TY)(Ill. C
2.degree.): 32.3% 41.5% a*.sub.t (Ill. C 2.degree.): -5.1 -7.0
b*.sub.t (Ill. C 2.degree.): +0.2 -2.5 R.sub.fY (Ill. C, 2 deg.):
22.3% 32.3% a*.sub.f (Ill. C, 2.degree.): -1.7 +6.5 b*.sub.f (Ill.
C, 2.degree.): +9.8 +11.0 R.sub.gY (Ill. C, 2 deg.): 16.2% 14.5%
a*.sub.g (Ill. C, 2.degree.): -1.1 -2.1 b*.sub.g (Ill. C,
2.degree.): -11.8 -10.2
[0037] It can be seen from the above that Example 1 had
surprisingly superior (lower) visible film side reflectance
(R.sub.fY) than the Comparative Example (CE), even though Example 1
also had lower visible transmission (TY) than the CE, namely 22.3%
in Example 1 compared to 32.3% in the CE. Thus, absorbing layers 4
and 25 in the middle and upper portions of the low-E coating in
Example 1 (as opposed to only in the center portion as in the CE),
coupled with removing the tin oxide layer from the CE's upper
dielectric stack, surprisingly caused the low-E coating to have a
combination of both (i) a low visible transmission, and (ii) low
visible film side reflectance. The layer thicknesses of Example 1
also surprisingly allowed more desirable optical characteristics to
be realized, compared to the CE.
[0038] In certain example embodiments of this invention, there is
provided a coated article including a coating 30 supported by a
glass substrate 1, the coating comprising: first and second
infrared (IR) reflecting layers 9 and 19 comprising silver, wherein
said IR reflecting layers 9 and 19 are spaced apart from one
another, and wherein the first IR reflecting layer 9 is located
closer to the glass substrate 1 than is the second IR reflecting
layer 19; a first substantially metallic or metallic absorption
layer 4 comprising Ni and/or Cr located such that the first
absorption layer 4 is located between the first and second IR
reflecting layers 9 and 19, wherein the first absorption layer 4 is
sandwiched between and contacting first and second dielectric
layers 14 and 14' comprising or consisting essentially of silicon
nitride; and a second substantially metallic or metallic absorption
layer 25 comprising Ni and/or Cr located such that both the first
and second IR reflecting layers 9, 19 are located between the glass
substrate 1 and the second absorption layer 25, wherein the second
absorption layer 25 is located between and contacting the second IR
reflecting layer 19 and a third dielectric layer 26 comprising
silicon nitride.
[0039] In the coated article of the immediately preceding
paragraph, said first and/or second absorption layers may each
comprise or consist essentially of NiCr and/or NiCrN.sub.x.
[0040] In the coated article of any of the preceding two
paragraphs, said first and/or second absorption layers may each
comprise from 1-15% nitrogen (atomic %).
[0041] In the coated article of any of the preceding three
paragraphs, said first and second IR reflecting layers are spaced
apart by at least, moving away from the glass substrate: a layer
comprising tin oxide 13, said first layer comprising silicon
nitride 14, said first absorption layer 4, said second dielectric
layer comprising silicon nitride 14', another layer comprising tin
oxide 15, and a layer comprising zinc oxide 17.
[0042] In the coated article of any of the preceding four
paragraphs, in certain example embodiments no metallic or
substantially metallic absorption layer is located between the
first IR reflecting layer and the glass substrate.
[0043] In the coated article of any of the preceding five
paragraphs, in certain example embodiments only two IR reflecting
layers comprising silver are contained in the coating.
[0044] In the coated article of any of the preceding six
paragraphs, the first absorption layer may be from about 35-75
angstroms (.ANG.) thick.
[0045] In the coated article of any of the preceding seven
paragraphs, the second absorption layer may be from about 23-48
angstroms (.ANG.) thick.
[0046] In the coated article of any of the preceding eight
paragraphs, the first absorption layer may be substantially thicker
than the second absorption layer.
[0047] In the coated article of any of the preceding nine
paragraphs, said coated article may have a visible transmission of
from about 20-43% (more preferably from about 24-36%), measured
monolithically.
[0048] In the coated article of any of the preceding ten
paragraphs, the coated article may be thermally tempered, or not
heat treated.
[0049] In the coated article of any of the preceding eleven
paragraphs, the coating in certain example embodiments may contain
no more than two metallic or substantially metallic absorption
layers consisting essentially of NiCr or NiCrN.sub.x.
[0050] In the coated article of any of the preceding twelve
paragraphs, the third layer comprising silicon nitride may be an
uppermost layer of the coating.
[0051] In the coated article of any of the preceding thirteen
paragraphs, said first IR reflecting layer and said first
absorption layer may be spaced apart by at least, moving away from
the glass substrate: a layer comprising an oxide of NiCr, a layer
comprising tin oxide, and the first layer comprising silicon
nitride.
[0052] In the coated article of any of the preceding fourteen
paragraphs, the coated article may have a visible film side
reflectance (RfY), measured monolithically, of less than or equal
to 26%, more preferably less than or equal to 24%.
[0053] In the coated article of any of the preceding fifteen
paragraphs, a substantially oxided layer comprising an oxide of
NiCr may be located over and directly contacting the first IR
reflecting layer.
[0054] While the invention has been described in connection with
what is presently considered to be the most practical and preferred
embodiment, it is to be understood that the invention is not to be
limited to the disclosed embodiment, but on the contrary, is
intended to cover various modifications and equivalent arrangements
included within the spirit and scope of the appended claims.
* * * * *